Combine checks and parsing of versioned packages (#1116)

## Summary

1. Move `IsVersionedPackage` from `lock` to `devpkg`
2. Change `IsVersionedPackage` to `ParseVersionedPackage` to combine
checking and parsing of packages (return name and version and a boolean
value indicating if the package is versioned)
3. Reuse `ParseVersionedPackage` in versioned packages checking and
parsing cases.

## How was it tested?

devbox update python
devbox update [email protected]

Author: hezhizhen

internal/devconfig/init.go

@@ -10,6 +10,7 @@ import (
 	"strings"
 
 	"github.com/fatih/color"
+
 	"go.jetpack.io/devbox/internal/cuecfg"
 	"go.jetpack.io/devbox/internal/initrec"
 )

internal/devpkg/pkg.go

@@ -0,0 +1,15 @@
+// Copyright 2023 Jetpack Technologies Inc and contributors. All rights reserved.
+// Use of this source code is governed by the license in the LICENSE file.
+
+package devpkg
+
+import (
+	"strings"
+)
+
+// ParseVersionedPackage checks if the given package is a versioned package (`[email protected]`)
+// and returns its name and version
+func ParseVersionedPackage(pkg string) (string, string, bool) {
+	name, version, found := strings.Cut(pkg, "@")
+	return name, version, found && name != "" && version != ""
+}

internal/lock/lockfile.go

@@ -11,8 +11,10 @@ import (
 	"strings"
 
 	"github.com/samber/lo"
+
 	"go.jetpack.io/devbox/internal/boxcli/featureflag"
 	"go.jetpack.io/devbox/internal/cuecfg"
+	"go.jetpack.io/devbox/internal/devpkg"
 )
 
 const lockFileVersion = "1"
@@ -73,7 +75,7 @@ func (l *File) Resolve(pkg string) (*Package, error) {
 	if entry, ok := l.Packages[pkg]; !ok || entry.Resolved == "" {
 		locked := &Package{}
 		var err error
-		if IsVersionedPackage(pkg) {
+		if _, _, versioned := devpkg.ParseVersionedPackage(pkg); versioned {
 			locked, err = l.resolver.Resolve(pkg)
 			if err != nil {
 				return nil, err
@@ -122,15 +124,11 @@ func (l *File) LegacyNixpkgsPath(pkg string) string {
 	)
 }
 
-func IsVersionedPackage(pkg string) bool {
-	name, version, found := strings.Cut(pkg, "@")
-	return found && name != "" && version != ""
-}
-
 // This probably belongs in input.go but can't add it there because it will
 // create a circular dependency. We could move Input into own package.
 func IsLegacyPackage(pkg string) bool {
-	return !IsVersionedPackage(pkg) &&
+	_, _, versioned := devpkg.ParseVersionedPackage(pkg)
+	return !versioned &&
 		!strings.Contains(pkg, ":") &&
 		// We don't support absolute paths without "path:" prefix, but adding here
 		// just in case we ever do.

internal/searcher/client.go

@@ -9,9 +9,9 @@ import (
 	"io"
 	"net/http"
 	"net/url"
-	"strings"
 
 	"go.jetpack.io/devbox/internal/boxcli/usererr"
+	"go.jetpack.io/devbox/internal/devpkg"
 	"go.jetpack.io/devbox/internal/envir"
 	"go.jetpack.io/devbox/internal/lock"
 	"go.jetpack.io/devbox/internal/nix"
@@ -52,7 +52,7 @@ func (c *client) SearchVersion(query, version string) (*SearchResult, error) {
 }
 
 func (c *client) Resolve(pkg string) (*lock.Package, error) {
-	name, version, _ := strings.Cut(pkg, "@")
+	name, version, _ := devpkg.ParseVersionedPackage(pkg)
 	if version == "" {
 		return nil, usererr.New("No version specified for %q.", name)
 	}